This disclosure relates to an optical fiber assembly, to methods of manufacture thereof and to articles comprising the same. In particular, this disclosure relates to an optical fiber assembly with a wide divergence angle and uniform light distribution, to methods of manufacture thereof and to articles comprising the same.
For optical fibers for illumination, the output divergence angle from the fiber is typically limited by its numerical aperture (NA). For example, using a 0.47 numerical aperture step index optical fiber, the full width at half maximum (FWHM) divergence angle is approximately 56 degrees. It is however desirable, to have wider divergence angles for some illumination applications. In the past, a ball lens, a concave or axicon lens was attached to the end of the fiber to increase the maximum divergence angle. However in this configuration, the output distribution is no longer uniform and this non-uniform distribution is undesirable for certain applications. There is therefore a need for obtaining an improved output divergence angle of greater than 56 degrees while at the same time obtaining a uniform light distribution.